1. Field of the Invention
The present invention relates to improvement in or relating to a photoelectric conversion device in which a number of semiconductor elements are sequentially arranged on a substrate in side-by-side relation and connected in series.
The invention also pertains to a method for the manufacture of such a photoelectric conversion device.
2. Description of the Prior Art
There has been proposed in U.S. Pat. No. 4,315,096 a photoelectric conversion device of the type wherein a plurality n (n being an integer greater than one) of semiconductor elements U.sub.1 to U.sub.n are sequentially formed side by side on a substrate having an insulating surface and are connected in series one to another.
According to this semiconductor photoelectric conversion device, the semiconductor element U.sub.i (i=1, 2, . . . n) has a first electrode E.sub.i formed on the substrate, a non-single-crystal semiconductor laminate member Q.sub.i formed on the first electrode E.sub.i to form at least one semiconductor junction and a second electrode F.sub.i formed on the non-single-crystal semiconductor laminate member Q.sub.i in opposing relation to the first electrode E.sub.i. The second electode F.sub.j+1 of the semiconductor element U.sub.j+1 (j=1, 2, . . . (n-1)) is coupled with the first electrode E.sub.j of the semiconductor element U.sub.j through a coupling portion K.sub.j formed as an extension of the second electrode F.sub.j+1.
With such a semiconductor photoelectric conversion device, electrical loss resulting from the contact resistance between the coupling portion K.sub.j and the first electrode E.sub.j is an obstacle to enhancement of the photoelectric conversion efficiency. For reducing the electrical loss to raise the photoelectric conversion efficiency, it is necessary that the contact resistance between the coupling portion K.sub.j and the electrode E.sub.j be low and be not increased by long-term use.
In the abovesaid conventional photoelectric conversion device, however, no consideration is paid to designing the coupling portion K.sub.j and the electrode E.sub.j to prevent the contact resistance therebetween from being increased by long-term use. Accordingly, this prior art device possesses the defect that its long-term use will impair the photoelectric conversion efficiency.
Further, in the photoelectric conversion device mentioned above, the coupling portion K.sub.j is shown to be coupled with the top surface of the first electrode E.sub.j. In this case, however, in order to obtain good contact between the coupling portion K.sub.j and the first electrode E.sub.j, it is necessary that the area of the contact portion in the lateral direction be increased. But this makes it impossible to form the photoelectric conversion device with high density.
Moreover, in the photoelectric conversion device of the abovesaid U.S. patent, it is shown that the coupling portion K.sub.j makes contact with the first electrode E.sub.j only at the outer side thereof. In this case, the contact area between the coupling portion K.sub.j and the first electrode E.sub.j is extremely small, so that good contact cannot be obtained between them.
Therefore, the aforementioned prior art has the defect that a photoelectric conversion device with low electrical loss cannot be obtained with high density.